Automatic thread cutter and needle positioner



S. M. COHEN Nov. 24, 1959 AUTOMATIC THREAD CUTTER AND NEEDLE POSITIONER3 Sheets-Sheet 1 Filed Jan. 17, 1957 ATTORNEY Nov. 24,1959 5,1, COHEN A2,914,010

AUTOMATIC THREAD CUTTER AND NEEDLE POSITIONER Filed Jan. 17, 1957 Tlcfi.

3 Sheets-Sheet 2 84 i v 70 I o I 76 f) I K 74/ 90 1 Ml r 96 99 @209 92 Il 4 4 f." .w g I I i I 4 l- 1| T m H T um 5 I I v o @l- T l I 74/ 76 A AO INVENTOR J 7! A2 CaHE/V ATTORNEY Nov. 24, 1959 s. M. COHE'N 2,914,010

AUTOMATIC THREAD (mm AND NEEDLE POSITIONER Filed Jan. 17, 1957 s Sheets-Sheet s I I T1:.7.

INVENTOR J19; 4?. tau/5w BYZQM ATTORNEY United States Patent "iceAUTOMATIC THREAD CUTTER AND NEEDLE POSITIONER Saul M. Cohen, Paramus,NJ., assignor to Clinton Indusgrfiasi2 Inc., New York, N.Y., acorporation of New Application January 17, 1957, Serial No. 634,770

Claims. (Cl. 112-252) The present invention relates generally toimprovements in sewing machines, and it relates more particularly to animproved device for use with a sewing machine for efiecting theselective automatic cutting of the sewing thread.

In domestic and commercial sewing operations employing conventionalsewing machines the frequent cutting of the sewing thread is necessary.This cutting of the thread is eflected either following each sewingsequence or the workpieces are connected in succession by the continuousthread and subsequently out. In either event the cutting of the threadis highly time consuming and inefficient and results in a large waste ofsewing thread. There have been many proposals for expediting the cuttingof the thread but these have been of a crude nature and contributed verylittle to the overall efiiciency of the sewing operation.

It is therefore a principal object of the present invention to providean improved sewing machine.

Another object of the present invention is to provide an improvedmechanism for automatically effecting the cutting of a thread in asewing machine.

Still another object of the present invention is to provide an improvedapparatus for automatically positioning a sewing machine needle andeffecting the cutting of the sewing thread.

A further object of the present invention is to provide an improvedmechanism for automatically positioning a sewing machine needle in anydesired position.

The above and other objects of the present invention will becomeapparent from a reading of the following description, taken inconjunction with the accompanying drawings, wherein Figure 1 is a frontelevational view of a sewing machine embodying the thread cuttingmechanism of the present invention shown partially broken away forconvenience of illustration;

Figure 2 is a rear elevational view thereof;

Figure 3 is a top plan view of the needle positioning mechanism;

I Figure 4 is a sectional view, taken along line 44 in Figure 3;

Figure 5 is a sectional view, taken along line 55 in Figure 3;

Figure 6 is an end elevational view illustrating a safety switchmechanism;

Figure 7 is a partial rear detail view illustrating the thread cuttingmotivating mechanism;

Figure 8 is a horizontal detailed sectional view showing the threadcutting mechanism;

Figure 9 is a sectional view, taken along line 9-9 in Figure 8;

Figure 10 is a schematic circuit diagram of the improved thread cuttingmechanism.

The present invention, in a sense, contemplates the provision of theimproved combination comprising a reciprocatable needle bar, a threadengaging needle carried by said needle bar, means motivating said needlePatented Nov. 24, 1959 bar to reciprocate said needle along apredetermined path, a thread cutting element movable across the path ofsaid needle, means for automatically positioning said needle above thelevel of said thread cutting element and means responsive to theposition of said needle above said thread cutting element to actuatesaid thread cutting element. 7

Referring now to the drawings, the numeral 10 generally designates abase upon which is mounted a sewing machine head 11 of substantiallyconventional construction including a cantilevered arm 12 carrying areciprocating needle bar 13 which removably holds a sewing needle 14.Also provided is a presser foot 1-6 movable between a depressed andraised position by cessed portion 36.

means of a lever 17 pivotally connected to the rear face of the arm 12and having a grooved forward end engaging a pin 18a which is connectedto the presser foot 16 in the usual manner. The rear end of the lever 17is adjustably coupled by a vertically movable connect-ing bar 18 to aknee treadle 19 in a conventional manner. Disposed below the presserfoot 16 is a cloth plate 20 which has longitudinal slots formed thereinwith which register the cloth advancing dogs 21.

The underface of the presser foot 16 is recessed and carries a soleplate 22 to define a housing 23 having aligned openings formed thereinto permit the passage of the sewing needle. A knife 24 is located in thehousing 23 and is rotatably carried by a crank 26 provided with arearwardly projecting arm 27 terminating in a balled end. The knife 24has a lower cutting edge 28 which cooperates with the stationary edge 29formed on the sole plate 22. Also carried by the knife 24 is a forwardlyprojecting raised 100p forming flange 30.

Disposed below the cloth plate 20 and spaced therefrom is a guide plate32. A reciprocating knife 33 is slidably located between the confrontingfaces of the cloth plate 20 and the under plate 32 and is provided withan upwardly sprung forward cutting edge which abuts the underface of theplate 20. The thread pulling member 34 is slidably located in abutmentwith and below the plate 32 and terminates rearwardly in a re- Thecutting plate 33 and the looping member 34 are connected by a lostmotion arrangement and the recessed portion 36 is engaged by the balledend of an arm of a pivoted bell crank 37, the other end of which isconnected to one end of an actuating rod 38.

The crank arm 27 is engaged by a longitudinally extending slot formed ina lever 39 pivoted at its midpoint to the presser foot bar so as to beoscillatable about a horizontal axis, the opposite end of the leverslidably engaging a vertical slot formed in the lower end of a bracketmember 40. A rod 41 is horizontally slidable in a support bracket 42mounted on the sewing machine head and carries the depending bracket 40.The opposite end of the rod 41 is pin connected to a verticallyextending arm 43 which has its upper end pivoted to the sewing machinehead 11. The lower end of the arm 43 is pin connected to the upper endof a second arm 44 which is pivoted to the sewing machine head 11 as at46 and has a depending portion engaging the rear end of the rod 38.Thus, upon the forward and rearward movement of the rod 41 the cuttingknife 24 is solenoids M2 and M3 are housed in a casing 47 which ismounted on the sewing machine head 11. The solenoids M2 and M3 areprovided with slidable arrnatures 48 and 49 respectively which areconnected by a link member 50 provided with a vertical groove 51engaging va pin 52 mounted on the rod 41. In normal operating-positionthe rod 41 and the corresponding solenoid armatures 48- and 49 are intheir .rearmost position. In order to effect the cutting operation, thesolenoid M3 is first energized to advance the rod 41 forwardly and thenthe solenoidMZ is energized and the solenoid M3 deenergized to effectthe retraction of the rod 41. The circuit for achieving the aforesaidenergization will be hereinafter set forth" and the mechanism of thethread. cutting operation has been described in the previously citedChudner patent.

The sewing machine head 11 is provided with a conventional hand wheel 53carrying a drive pulley 54 which is connected by way of a V-belt 56 to apower pulley 57.

The power pulley 57 is rotatably carried by a bracket 58 and may beselectively coupled by way of a clutch mechanism to a main drive motor59 or a brake plate. The clutch mechanism is for effecting the drivingor braking of the pulley '7 and the sewing machine and is controlled bymeans of a rod 60 connected to the foot treadle of the sewing machine.The above braking and drive control mechanism is conventional. It shouldbe noted that by control of the rod 60 and the various parts connectedthereto the clutch may be located at the position intermediate thebraking and driving position so that the hand wheel 53 may be rotatedindependent of the drive motor and the brake plate.

In order to automatically effect the aforesaid intermediate positioningof the clutch there is provided a lever 61 pivotally connected to asupport bracket 63, the forward end of the lever 61 carrying an anglemember 64 which is adapted to bear upon the upper end of the control rod60 when the arm 61 is rotated clockwise and is free of the movement ofthe control rod 60 when the lever 61 is in its counterclockwisemostposition. The opposite end of the lever 61 is connected to the armatureof a solenoid M1 the actuation of which will be hereinafter described.

In order to effect the thread cutting operation it is necessary that theneedle 14 and the needle bar 13 be located in a raised position. Themechanism for automatically positioning the needle in raised positionand effecting the actuation of the thread cutting device, and ifdesired, for selectively positioning the needle in its depressedposition or raised position including an auxiliary drive motor 70suitably mounted on the base adjacent the drive end of the sewingmachine head 11 and connected to the input end of a right angle gearreduction unit 71. The gear reduction unit 71 is provided with an outputshaft 72 which carries a sprocket wheel 73;

A pair of horizontally spaced parallel vertical blocks 74 have alignedopenings formed therein which engage respective ball bearing members 76.A shaft 77 passes through and is rotatably engaged by the ball bearingmembers 76 and carries at its rear end an overrunning clutch couplingdevice 78 which is secured and positively positioned on the shaft 77 bymeans of a nut 79 which engages the threaded end of the shaft 77. Thedriven member 80 of the overrunning clutch 78 is rigidlyalfixed to theshaft 77 whereas the drive member 81 is rotatably carried thereby and itis in drive relationship with the driven member 80 and the shaft 77 onlywhen the drive member 81 rotates at a greater speed than the drivenmember 80. There is no intercoupling between the clutch members 80 and81 when the driven member 80 is rotated at a greater speed than thedrive member 81.

The drive member 81 carries a sprocket wheel 82 which is connected byway of a sprocket chain 83 to the sprocket wheel 73. Mounted on theforward end of the shaft 77 is a sprocket wheel 84 which isconnected'b'y way of a sprocket chain 86 to a sprocket wheel 87 afiixedto' the 4 l sewing machine hand wheel 53 so that the shaft 77 rotateswith the hand wheel 53 and with the needle bar drive mechanism. Thus,when the sprocket wheel 73 is stationary or is driven by way of theauxiliary drive motor 70 so that the clutch drive member 81 rotates at aspeed less than the driven member there is no drive coupling between theauxiliary drive motor 70 and the shaft 77 A pair of base plates 90 arecarried on the inner face of each of the blocks 74. Mounted on'theconfronting faces of the base plates 90 are breaker point mechanisms B1and B2 respectively each of which includes a bracket member 91adjustably afiixed to the base plate 90 by means of screws 92 engagingslots formed in the enlarged ends of the brackets 91 and engaging tappedopenings in the base plate 90. The bracket 91 carries a pin 94 whichrotatably supports a rocking breaker arm 96, one end of which isprovided with a circular opening engaging an insulator bushing carriedon the pin 94. The free end of the breaker arm 96 is provided on itslower face with a contact point 97. The pin portion of the rocker arm 96carries a flexed spring member 98, the free end of which is providedwith an opening slidably engaging a stud 99 carried by an upwardlydirected ear 100 disposed on the bracket 91. The tension on the spring98 is adjustable by means of a nut 101 engaging the stud 99. The lowerforward end of the bracket 91'is provided with an upstanding lug 102which carries a stationary contact point 103 in registry with thebreaker point 97. It should be noted that the breaker arm 96 and thebreaker point 97 are electrically separated from the contact point 103and its supporting mechanism in the manner well known.

Each of the breaker arms 96 is provided in the conventional manner witha depending cam follower 104 which engages the surface of a respectivecylindrical cam 105 and 106 carried by and rotatable with the shaft 77.Each of the cams 105 and 106 is provided with a raised surface 108, thebreaker points 97 and 103 being separated when the cam follower 104engages the raised surface 108 of the respective cams 105 and 106 andare in closed position when the cam follower 104 registers with thedepressed portions 109 of the cams 105 and 106. It should be noted thatthe respective cams 105 and 106 are carried on the shaft 77 so thattheir raised portions 108 are separated approximately 180". The angularposition of the cam 105 is such that when the needle bar 13 and theneedle 14 are in depressed or lowermost position the raised portion 108of the cam 105 engages the cam follower 104 and when the needle bar 13and needle 14 are in their raised position the corresponding camfollower 104 registers with the raised surface 108 of the cam 106. Thus,when the needle is in depressed position the breaker switch B1 is closedand breaker switch B2 open and when the needle is in its raised positionthe breaker switch B2 is closed and the breaker switch B1 is open.

A switch S7 is carried on a bracket 110 adjacent to the presser footactuating control rod 18. An actuating arm 111 is carried by the switch110 and engages the underface of the free end of the presser foot lever17. When the presser foot 16 is in its raised position the rear end ofthe lever 17 depresses the arm 111 to effect the opening of the normallyclosed switch S7. However, when the presser foot is in its depressedposition the rear end of the lever 17 is raised to effect the closing ofthe switch S7. A switch S6 is provided with an actuating plunger 112which engages the underface of the inner end of the clutch plate controllever 61. The switch S6 is normally closed and is opened upon actuationof the'sole noid M1. The purpose of the switch S6 is to prevent multiplecycling of the cutting operation as will be hereinafter set forth.

Referring now more particularly to Figure .10'of the drawing whichschematically illustrates the wiring and electrical components of theimproved device, the designation L1 indicates a conductor line which isconnected by way of a main switch S1 to one terminal of a source ofalternating current 120, the other terminal of which is connected to aline L2. A hand operated single pole double throw switch S3, which isreadily accessibleand carried on the sewing machine head 11, has its armconnected to the line L2 and one pole P3 thereof connected to the arm 96of the breaker mechanismBl and the other pole P32 connected to the arm96 of the breaker mechanism B2. A normally open single throw double poleswitch S2 is closed by an auxiliary knee peddle 121 depending from thesewing machine base and laterally spaced from the knee treadle 19. a Oneof the arms B22 of the switch S2 is connected to the line L2 and theother arm B21 thereof is connected by way of the switch S6 to the arm A1actuated .by the relay R1,

the cooperating contact of which is connected to'one terminal of thesolenoid of the relay R2. The other terminal of the relay R2 isconnected to the line L1. Both of the poles of the switch S2 areconnected to;the arm 96 of the breaker mechanism B2. The contactelements 103 of the breaker mechanism B1 and B2 are connected to a lineL3. The clutch actuating solenoid M1 and the solenoid of the relay R1are connected between the lines L1 and L3. The line L3 is also connectedby way of a filter condenser C1 to one pole D1 of an alternating currentinduction motor D, the other pole of which is connected to the line L1.

A contact P110 associated with its arm All which is actuated by therelay R1 and connected to the motor pole D1, is connected to the lineL3. An opposite pole P111 associated with the relay arm A11 is connectedto one side of a rectifier F and through a braking condenserCZ to' lineL1. The other side of the rectifier F is connected through a resistor Rto the line L3. The relay R2 actu ates an arm A2 which is connected tothe line L2 andalternately engages contact P20 which is connectedthrough the presser foot control safety switch S7 to one terminal of thesolenoid M2, the other terminal of which is connected to the line L1 andcontact P21 which is connected to one end of the terminal M3, the otherterminal of which is connected to the line L1. It should be noted thatwhen the solenoid of the relay R1 is energized the relay arm A1 is inopen position and the arm A11 engages the contact P110 and when thesolenoid of the relay R2 is energized the arm A2 engages the contactP20.

Considering now the operation of the improved sewing machine, upontermination of the sewing cycle, the operator releases the foot treadlepermitting the raising of the drive control rod 60 so that the clutchswings from the motor engaged position to the braking position therebystopping the sewing machine. He thereupon actuates the knee treadle 121to close the switch S2 bringing the arms B22 and B21 into engagementwith the respective switch poles. In the event that the needle bar 13and needle 14 are not in their raised position the raised portion 108 ofthe cam 106 will be out of registry with the cam follower 104 so thatthebreaker mech anism B2 is in closed position to complete the circuitconnecting the solenoid M1 and the solenoid of relay R1 across the linesL1 and L2 to energize the solenoids. The energization of the solenoid Mldepresses the rod 60 slightly to release the main drive brake to permitthe rotation of the pulley 54 and movement of the needle bar and needles13 and 14 respectively. Furthermore, the energized relay R1 swings thearm A1 to open position so that the circuit to the relay R2 is open, andpulls the arm A11 into engagement with the contact P110 to connect themotor D between the power lines L1 and L2 by way of the breakermechanism B2 and the switch S2.

The energized motor D drives the sewing machine by way of the reductiongear 71, shaft 77 and the associated overrunning clutch 78 and thevarious sprocket wheels and sprocket chains. When the needle bar 13 andnee dle 14 reach their upper position the raised portion 108 of the cam106 registers with the corresponding cam follower 104 to open thebreaker mechanism B2 to thereby deenergize the solenoid M1 and brake thesewing machine. The deenergized relay R1 permits the arm A11 to returninto engagement with the contact P111 and the arm A1 to return to closedposition to thereby energize the solenoid of the relay R2. As the armA11 engages the contact P'll the condenser C2 which has been previouslycharged by way of the rectifier F and resistor R is connected across themotor D to rapidly dynamically brake the motor D. The energization ofthe solenoid of the relay R2 brings the arm A2 out of engagement withthe contact P21 and into engagement with the contact P20to energize thesolenoid M2 which in turn carries the cutter actuating bar 41 to itsrear position. The knee treadle is thereafter released to permit theswitch S2 to open thereby deenergizing the relay R2 and permitting thearm A2 to return to engagement with the contact P21 and out ofengagement with the contact P20 thereby deenergizing the solenoid M2 andenergizing the solenoid M3 and returning the rod 41 to its forwardposition to complete the cutting operation. The reciprocating motion ofthe rod 41 mechanically effects the cutting operation as has beenhereinbefore set forth.

In the event that it is desired to automatically bring the needle bar 13and needle 14 to its depressed position the toggle switch S3 ismanipulated to bring the arm thereof into contact withthe pole P3 whichenergizes the solenoid M1 to relieve the drive brake and energizes thesolenoid of the relay R1 to raise the arm A11 into engagement with thecontact P1'10 completing the circuit to the auxiliary drive motor Dwhich drives the sewing machine through the shaft 77 until the raisedportion 108 of the cam engages the corresponding cam follower 104 toopen the breaker mechanism B 1 and deenergize the solenoid M1 and thesolenoid of the relay R1 permitting the arm A11 to return intoengagement with the pole P111 effecting the dynamic braking of theauxiliary drive motor D.

Inasmuch as the switch S2 has been maintained in open position thecutting operation is not affected. By manipulating the toggle switch S3in an opposite direction to effect engagement of the pole P32 the needlemay be automatically located in its upper position without the actuationof the cutting mechanism in the manner similar to that for automaticallylocating the needle in its depressed position as above described.

It will be noted that when the presser foot 16 is in its raised positionthe switch S7 is opened as aforesaid thereby preventing the energizationof the solenoid M2 and the efiecting of the cutting operation. It shouldalso be noted that when the solenoid M1 is energized the switch S6 isopened by the swinging of the lever 61. Thus, in the event of multiplecycling which may occur when the operator actuates the main drive foottreadle as well as well as the knee peddle 121 the switch S6 because ofthe inertia of the system will be maintained open during the opening ofthe breaker mechanism B2 to thereby prevent the energization of thesolenoid of the relay R2 and the successive repetitive recycling of thethread cutting operation.

While there has been described and illustrated a preferred embodiment ofthe present invention, it is apparent that numerous alterations andomissions may be made without departing from the spirit thereof.

1 claim:

1. The improved combination comprising a sewing machine including areciprocable needle bar, a thread engaging needle carried by said needlebar, means motivating said needle bar to reciprocate said needle along apredetermined path, a thread cutting element movable across the path ofsaid needle, means for stopping said needle bar and said needle,automatically operable means for thereafter selectively positioning saidneedle above the level of said thread cutting element, means responsiveto the positioning of said needle above said thread cutting element toactuate said thread cutting element, and means to deactivate the lastreferred-to means thereby to prevent the thread cutting, as desired,when the needle is positioned above the thread cutting element.

2. The improved combination in accordance with claim 1, including asecond thread cutting element disposed below said first thread cuttingelement, and a cloth supporting plate located between said threadcutting elements.

3. The improved combination comprising a sewing machine including areciprocatable needle bar, a thread engagingneedle carried by saidneedle bar, a thread cutting element movable across the path of saidneedle, a main drive motor, means including a clutch coupling said maindrive motor to said needle bar, said clutch being movable intoengagement with said drive means, into braking position, and into aposition intermediate said drive means engaging position and saidbraking position, a first solenoid including an armature adapted toshift said clutch into said intermediate position upon energization ofsaid first solenoid, an auxiliary motor connected to said needle barthrough an overrunning clutch, a first normally open selectivelyoperable switch, a second normally openswitch responsive to the positionof said needle bar to be closed when said needle bar is in a raisedposition, said first solenoid and said first and second switches beingconnected in series across a source of current, a first relay having asolenoid connected in series with said first and second switches acrossa source of current, a pair of first relay contacts associated with saidfirst relay, a pair of normally closed relay contacts movable to openposition upon energization of said first relay solenoid, a third switchoperable concurrently with said first switch, a second relay having asolenoid connected in series with said first contact points and saidfirst and third switches to a source of current, a contact carrying armactuated by said first relay and a second normally engaging and a thirdnormally disengaged contact registering therewith, said auxiliary drivemotor having one pole connected to one terminal of a source of currentand the other pole being'con nected to said first relay arm and saidthird contact being connected through said first and second switchesto'the other terminal of said source of current, a secondcontactcarrying relay arm associated with said second relay, a fourth contactregistering with and normally out of en'- gagement with said secondrelay arm and a second solenoid having an armature connected to saidthread cutting element and having one terminal connected to one pole ofa source of current and the other terminal connected to said thirdcontact, said second relay arm being connected to the other terminal ofsaid source of current.

4. The improved combination in accordance with claim 3, including acapacitor connected in series with a rectifier and said first and secondswitches to a source ofcur rent, one-terminal of said capacitor beingconnected to one pole of said auxiliary drive motor and the otherterminal of said capacitor being connected to said relay second contact.

5. The improved combination in accordance with claim 3, including afourth normallyopen switch responsive to the position of said needle barto be closed when said needle bar is in depressed position, and afifthnormally open selectively operable switch, said fourth and fifth'switches being connected in series across said first and secondswitches.

References Cited in the file of this patent UNITED STATES PATENTS1,592,115 Lindgren July 13, 1926- 2,037,721 Haas Apr. 21, 1936-2,201,969 Haas May 21, 1940 2,226,401 Haas Dec. 24, 1940 2,376,417Chudner May 22, 1945 2,517,567 Hill et a1. Aug. 8, 1950 2,707,927 Artztet al. May 10, 1955' 2,759,444 Schwab et a1 Aug. 21, 1956 FOREIGNPATENTS 744,660 Great Britain Jan. 21, 1953

